POS0033 RISK OF OSTEOARTICULAR INFECTION AND DEATH FOLLOWING STAPHYLOCOCCUS AUREUS BACTEREMIA IN PATIENTS WITH AND WITHOUT RHEUMATOID ARTHRITIS – A DANISH NATIONWIDE REGISTRY-BASED COHORT STUDY
Authors: S. Dieperink, B. Glintborg, M. Nørgaard, F. Mehnert, L. B. Oestergaard, T. Benfield, C. Torp-Pedersen, A. Petersen, M. L. Hetland
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Patients with rheumatoid arthritis (RA) are at increased risk of <i>S. aureus</i> bacteremia (SAB) compared with the general population.[1] SAB has high mortality and osteoarticular infection (OAI) is a feared complication associated with persistent pain and disability. It remains unclear if RA is associated with increased risk of OAI or death following SAB. [2, 3] <h3>Objectives</h3> To compare risk of OAI and death in SAB patients with and without RA and to assess risk factors for OAI in RA patients including risk associated with antirheumatic treatment. <h3>Methods</h3> Nationwide cohort study of Danish patients with microbiologically verified first-time SAB from 1 January 2006 to 31 December 2018. We identified RA, OAI, vital status, comorbidities, and RA-related clinical characteristics in the rheumatology registry, DANBIO and other national registries. We estimated 90-day cumulative incidence of OAI (in patients without OAI before SAB) and all-cause mortality (all patients). We computed hazard ratios (HR) by multivariate Cox regression adjusted for a priori known risk factors for each outcome. <h3>Results</h3> We identified 18,274 patients with SAB (n=367 with RA). In RA versus (vs.) non-RA, women comprised 62% vs. 37% and median age was 73 years (interquartile range 65; 80) vs. 70 years (59; 82). Prior OAI (0-3 months before SAB) was diagnosed in 4% vs. 2%. The 90-day cumulative incidence of OAI was 23.1% (95% CI 18.8; 27.6) in RA patients vs. 12.5% (12.1; 13.0) in non-RA (<b>Figure 1</b>) (HR 1.93 (1.54; 2.41) adjusted for age, sex, calendar year, and diabetes mellitus). In RA, use of tumor necrosis factor inhibitors (TNFi) and orthopedic implants were associated with OAI risk (<b>Table 1</b>). Mortality was similar in SAB patients with (35.4% (30.6; 40.3)) and without RA (33.9% (33.2; 34.5) (Figure), (HR 1.04 (0.87; 1.24) adjusted for age, sex, calendar year, chronic liver disease, chronic obstructive pulmonary disease, cancer, congestive heart failure, renal failure). <h3>Conclusion</h3> Nearly one in four patients with RA experienced an osteoarticular infection following <i>S. aureus</i> bacteremia compared with one in eight patients without RA. In patients with RA, current TNFi use and orthopedic implants were associated with increased osteoarticular infection risk. One in three patients died, with no difference between patients with and without RA. These findings highlight the need for vigilance when RA patients present with SAB to ensure timely identification of OAI. <h3>References</h3> [1]Dieperink et al, DOI: 10.1080/03009742.2022.2049057 [2]Joost et al, DOI: 10.1016/j.jinf.2017.03.003 [3]Sams et al, DOI: 10.1007/s00296-015-3239-8 <h3>Acknowledgements</h3> We wish to thank The Danish Rheumatism Association and Beckett-Fonden for their financial support and patient representative Pia Lüchau Pedersen for her inputs. <h3>Disclosure of Interests</h3> Sabine Dieperink: None declared, Bente Glintborg Grant/research support from: All outside the submitted work: Pfizer, BMS, Sandoz, Mette Nørgaard: None declared, Frank Mehnert: None declared, Louise Bruun Oestergaard: None declared, Thomas Benfield Speakers bureau: GSK, Pfizer, Gilead, Boehringer Ingelheim, MSD, Astra Zeneca, Janssen, Pentabase ApS, Grant/research support from: All outside the submitted work: Novo Nordisk Foundation, Simonsen Foundation, Lundbeck Foundation, Kai Hansen Foundation, Erik and Susanna Olesen's Charitable Fund, GSK, Pfizer, Gilead, Christian Torp-Pedersen Grant/research support from: All outside the submitted work: Novo Nordisk and Bayer, Andreas Petersen: None declared, Merete Lund Hetland Grant/research support from: All outside the submitted work: Abbvie, Biogen, BMS, Celltrion, Eli Lilly, Janssen Biologics B.V, Lundbeck Fonden, MSD, Pfizer, Roche, Samsung Biopies, Sandoz, Novartis.